Hello, GV126c4.
Welcome to Apple Support Communities.
From reading your post, it's understood the Find My AirPods feature isn't playing sounds when testing to hear the sound. We'd like to help. How long have you let the sound play? How to find your lost AirPods
"Play a sound
If your AirPods are near any of your Apple devices and connected to Bluetooth, you can play a sound to help you find them from iCloud.com or the Find My app. Your AirPods play a sound that gets gradually louder for two minutes, or until you tell them to stop.
- Open the Find My app.
- Select the Devices tab.
- Choose your AirPods from the list.
- Tap Play Sound.
Make sure that you remove the AirPods from your ears before you play a sound".
Also, check out this section from the same article:
"If your AirPods are offline
If you didn't turn on Find My [device] before your AirPods went missing, you can't use it to locate your device. If you see "No location found" under your AirPods, you can't play a sound to find them but you might be able to get directions to the location where they were last connected. If your AirPods do come back online, you'll get a notification on the iPhone, iPad, or iPod touch you use them with.
Find My is the only way that you can track or locate a lost or missing device. There is no other Apple service that can find, track, or otherwise flag your device for you".
Keep us updated.
Cheers!